Hi! I understand that Best Fiends lags just after you complete a level when you're playing offline on your Android device with WebKit. Let's get this sorted out together.

Could you tell me if the lag happens consistently right after every level completion, or just sometimes? Also, have you tried playing the game online to see if the lag still occurs?

In the meantime, here are some steps to try to ease the lag issue:

1. Clear Cache for Best Fiends
- Go to your device's Settings > Apps > Best Fiends.
- Tap on Storage and then 'Clear Cache'. This removes temporary files that might be causing slowdowns without deleting your game data.

2. Check for App Updates
- Make sure you have the latest version of Best Fiends installed from the Google Play Store. Updates often include performance fixes.

3. Close Background Apps
- Close other apps running in the background to free up memory, which can improve game performance.

4. Restart Your Device
- A simple reboot can help clear temporary system slowdowns.

5. Free Up Storage Space
- Ensure your device has enough free storage because low space can cause lag.

If the lag happens only offline, it might be related to the game's attempt to sync progress or access certain assets when no internet is available.

If these steps don’t help, you could try reinstalling the app, but please be sure your game progress is linked to an account or backed up to avoid losing data.

Let me know what happens after trying these, and if the lag persists, I can guide you with deeper troubleshooting or contact the support team for you. Are you satisfied with these steps so far?